With the rapid development of mobile devices, more and more mobile devices start to adopt a dual-screen design, namely, both front and back surfaces of a mobile device are provided with a display screen. For example, a liquid crystal display (LCD) screen or an organic light-emitting diode (OLED) screen may be arranged on a front surface of a mobile device as a first screen, and an E-ink screen may be arranged on a back surface of the mobile device as a second screen.